In the following, a nonwoven fabric including papermaking fibers relates to an absorbent paper which is also called nonwoven or web made of fibers like air-laid web in this field of technology. A typical absorbent paper has a basis weight, in the range from 30 to 250 g/m2, or 45 to 75 g/m2 for the table top range product.
FIG. 1 is a schematic representation of a known pattern 1 of a calendering roller that is used to manufacture textured nonwoven fabric including papermaking fibers. FIG. 2 schematically shows an enlarged view of said pattern. The pattern 1 includes multiple cavities 2 (appearing as circular dots in white in FIG. 1) arranged according to rows and columns and also multiple horizontal channels 3 and vertical channels 4 (appearing as straight lines in white in FIG. 1) substantially overall a peripheral surface of the calendering roller. The pattern 1 is a negative pattern meaning that the cavities and channels bottoms are below the contacting surface 5 as best seen in FIGS. 3 and 4 which represents cross-sectional views according to lines AA and BB of FIG. 2, respectively. A first drawback of this calendering roller is that the contacting surface 5 is important. A second drawback of this calendering roller is that the pattern easily gathers papermaking fibers and becomes dirty as a result of the compression during the calendering process. In particular, some of the cavities may be fouled up with an aggregate of papermaking fibers 6. This results in a produced textured nonwoven fabric including papermaking fibers, which is of low quality and includes “dark points”, low quality meaning that the resulting textured nonwoven fabric including papermaking fibers, is not well perceived by the consumers. The “dark points” are formed by a localized high density of papermaking fibers. This occurs when such aggregates of papermaking fibers are released from the cavity and incorporated into the textured nonwoven fabric including papermaking fibers during the calendering process. This is particularly noticeable for pattern having a density of dots ranging between 65 and 120 dots/cm2, and more particularly ranging between 70 and 90 dots/cm2. Further, these “dark points” affect both white and colored nonwoven fabric including papermaking fibers (though more visible on colored product).
There is a need to improve the aesthetic quality of the textured nonwoven fabric including papermaking fibers, and in particular to avoid the appearance of “dark points” in the textured nonwoven fabric including papermaking fibers so as to produce a cloth-like textured paper that is appealing to the eyes of the consumers.